Test Code C5FX
C5 Complement, Functional, Serum

Performing Laboratory

Useful For

Investigation of a patient with an undetectable total complement
(CH50) level

Method Name

Automated Liposome Lysis Assay

Reporting Name

C5 Complement, Functional, S

Specimen Type

Serum Red

Advisory Information

The total complement (CH50) assay (COM / Complement, Total, Serum)
should be used as a screen for suspected complement deficiencies
before ordering individual complement component assays. A
deficiency of an individual component of the complement cascade
will result in an undetectable total complement level.

Specimen Required

Patient Preparation:
Fasting preferred

Supplies: Aliquot
Tube, 5 mL (T465)

Collection
Container/Tube: Red top

Submission
Container/Tube: Plastic, 5 mL tube

Specimen Volume: 1
mL

Collection
Instructions:

1. Immediately after specimen collection, place the tube on wet
ice.

2. Centrifuge and separate serum from clot.

3. Immediately freeze specimen.

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type

Temperature

Time

Serum Red

Frozen

14 days

Reject Due To

Hemolysis

Mild OK; Gross OK

Lipemia

Mild OK; Gross reject

Icterus

Mild OK; Gross OK

Other

Serum gel tube

Reference Values

29-53 U/mL

Interpretation

Low levels of complement may be due to inherited deficiencies,
acquired deficiencies, or due to complement consumption (eg, as a
consequence of infectious or autoimmune processes).

Absent C5 levels in the presence of normal C3 and C4 values are
consistent with a C5 deficiency. Absent C5 levels in the presence
of low C3 and C4 values suggest complement consumption.

Day(s) and Time(s) Performed

Monday through Saturday; Continuously with a 3 p.m. cutoff

Analytic Time

Same day/1 day

Specimen Retention Time

14 days

Test Classification

This test was developed and its performance characteristics
determined by Mayo Clinic in a manner consistent with CLIA
requirements. This test has not been cleared or approved by the
U.S. Food and Drug Administration.